Multiplicity of dislocation pathways in a refractory multiprincipal element alloy

FL Wang and GH Balbus and SZ Xu and YQ Su and J Shin and PF Rottmann and KE Knipling and JC Stinville and LH Mills and ON Senkov and IJ Beyerlein and TM Pollock and DS Gianola, SCIENCE, 370, 95-+ (2020).

DOI: 10.1126/science.aba3722

Refractory multiprincipal element alloys (MPEAs) are promising materials to meet the demands of aggressive structural applications, yet require fundamentally different avenues for accommodating plastic deformation in the body-centered cubic (bcc) variants of these alloys. We show a desirable combination of homogeneous plastic deformability and strength in the bcc MPEA MoNbTi, enabled by the rugged atomic environment through which dislocations must navigate. Our observations of dislocation motion and atomistic calculations unveil the unexpected dominance of nonscrew character dislocations and numerous slip planes for dislocation glide. This behavior lends credence to theories that explain the exceptional high temperature strength of similar alloys. Our results advance a defect-aware perspective to alloy design strategies for materials capable of performance across the temperature spectrum.

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